Sahih Muslim
The Book of Faith (Kitab Al-Iman)
Book Number: 001 / Hadith Number: 260
It is narrated on the authority of Thabit, that when 'Abdullah b. 'Amr and 'Anbasa b. Abi Sufyan were about to fight against each other, Khalid b. 'As rode to 'Abdullah b. 'Amr and persuaded him (not to do so). Upon this Abdullah b. 'Amr said: Are you not aware that the Messenger of Allah (may peace be upon him) had observed:" He who died in protecting his property is a martyr."
This hadith has been narrated by Muhammad b. Hatim, Muhammad b. Bakr, Ahmad b. 'Uthman Naufali, Abu 'Asim, Ibn Juraij.